There have been a great variety of organic phosphites proposed for use as stabilizers for polymers, including the polyolefins. While some of these organic phosphites are available commercially, very few of them are completely satisfactory; and they are all expensive. Less expensive phosphorous containing chemicals that are readily prepared by incomplex methods and that have utility as stabilizers for polymers, particularly for polyolefins such as polypropylene, are needed. A further advantage would be that such phosphorous containing materials would enhance the stabilizing activity of hydroxyphenylalkyleneyl isocyanurates.